The Labor announced Sunday that it would postpone its primary two days to November 29.
Both Labor and Likud are using the same company for computer services, and the original dates - November 27 and November 25 - did not leave enough time to prepare for the second primary.
Over 60,000 Labor members have the right to choose the party's list for the 19th Knesset. Labor will have close to 300 ballot boxes in 60 computerized voting sites throughout Israel.
Labor Secretary-General Hilik Bar said that the primary will be "a celebration of democracy, that will be transparent and clean, and we are happy to have so many candidates running."